CI flake: v8 unreachable code error

[clockwork-labs-bot]

Created by CI Gremlin from a manually supplied failed GitHub Actions job.

Tests:

• TypeScript - Tests

Error:
. build: # Fatal error in , line 0
. build: # unreachable code
ERR_PNPM_RECURSIVE_RUN_FIRST_FAIL spacetimedb@2.6.0 build: pnpm -s build:js && pnpm -s build:types
Command failed with signal "SIGTRAP"

Failed job runs:

• https://github.com/clockworklabs/SpacetimeDB/actions/runs/27660030388/job/81802335478 (TypeScript - Tests, attempt manual -> n/a)

Context:

• Manual failed-job flake ticket.
• Job URL: https://github.com/clockworklabs/SpacetimeDB/actions/runs/27660030388/job/81802335478
• Run: 27660030388
• Job: 81802335478
• Head: fc47257d85e026593079227fc9d74c28b70ec2ac

[clockwork-labs-bot]

Investigation notes from the recent failures:

• The failures I checked are the same signature, not test assertions:
  • https://github.com/clockworklabs/SpacetimeDB/actions/runs/27660030388/job/81802335478
  • https://github.com/clockworklabs/SpacetimeDB/actions/runs/27700889060/job/81936659790
  • https://github.com/clockworklabs/SpacetimeDB/actions/runs/27729701919/job/82034156218
• All three jobs are on self-hosted Ubuntu and actions/setup-node resolves node-version: 22 to Node v22.22.3:
  • Acquiring 22.22.3 - x64 from https://github.com/actions/node-versions/releases/download/22.22.3-25838401827/node-22.22.3-linux-x64.tar.gz
• The crash happens while building crates/bindings-typescript with tsup v8.5.0:
  • spacetimedb@2.6.0 build: pnpm -s build:js && pnpm -s build:types
  • Fatal error in , line 0
  • unreachable code
  • Command failed with signal "SIGTRAP"
• The native stack is inside V8 Turboshaft lowering, e.g. MachineLoweringReducer::ReduceTruncateJSPrimitiveToUntagged, so this is an internal Node/V8 abort triggered by the tsup build workload.
• I do not see a checked-in pnpm-lock.yaml, tsup, or TypeScript dependency bump that explains the sudden change. The first ticketed failure is on Use SpacetimeDBGuard for SDK test suite #5340, which changed SDK test harness/source shape but not the TS build toolchain. That may have made the optimizer path easier to hit, but valid TS code should not crash Node with SIGTRAP.

Likely mitigation: pin the affected CI jobs away from floating node-version: 22 / Node 22.22.3. The most conservative pin is 22.21.1; alternatively try Node 22.23.0 or Node 24 in a PR. I would avoid leaving these jobs on floating 22 until this is proven fixed, because it makes the CI failure mode nondeterministic.

[clockwork-labs-bot]

Follow-up on why this started showing up recently:

• This is not explained by actions/setup-node suddenly moving to Node 22.22.3. A successful TypeScript - Tests run for head fc47257d at 2026-06-17T00:21:48Z also used Node v22.22.3 and completed both tsup v8.5.0 SDK builds.
• The same head fc47257d then failed at 2026-06-17T01:40:55Z with the V8 unreachable code / SIGTRAP abort during the recursive crates/bindings-typescript build. So the failure is nondeterministic on identical source + Node version.
• The strongest repo-side timing correlation is Fix TypeScript optional row keys #4940 (934158a36, merged 2026-06-16T17:13:48Z), which changed the TypeScript SDK source/type graph in crates/bindings-typescript/src/lib/type_builders.ts and several SDK generic surfaces. That is exactly the package being compiled by tsup when Node aborts.
• Use SpacetimeDBGuard for SDK test suite #5340 is where the first ticketed failure appeared, but it is not the best root cause candidate. Use SpacetimeDBGuard for SDK test suite #5340 is after Fix TypeScript optional row keys #4940 and the crash happens during SDK package build startup, before the SDK runtime tests exercise the new per-test server guard.
• Confirmed exact-signature failures I found after Fix TypeScript optional row keys #4940:
  • 2026-06-17T01:40:55Z, run 27660030388, job 81802335478, TypeScript - Tests, head fc47257d
  • 2026-06-17T03:25:27Z, run 27660106111 attempt 4, job 81813119035, Test Suite, head 34213f05
  • 2026-06-17T15:37:12Z, run 27700889060, job 81936659790, TypeScript - Tests, head 1747ca6c

Current diagnosis: #4940 likely changed the TS SDK input enough to make a Node 22.22.3 / V8 Turboshaft optimizer bug reachable. It remains a Node/V8 abort, not a TypeScript test failure, because the same source can pass and a JS process should not terminate with V8 unreachable code.

Best next diagnostic would be one PR or branch that only changes CI Node for TS-building jobs, then reruns the affected jobs repeatedly:

1. try Node 22.23.0 or 24
2. if we need minimum churn, pin to known older 22.21.1
3. if the flake persists across Node versions, then bisect the Fix TypeScript optional row keys #4940 TS type-shape change separately